FeCoCuMnRuB Nanobox with Dual Driving of High-Entropy and Electron-Trap Effects as the Efficient Electrocatalyst for Water Oxidation.

High-entropy borides hold potential as electrocatalysts for water oxidation. However, the synthesis of the tailored nanostructures remains a challenge due to the thermodynamic immiscibility of polymetallic components. Herein, a FeCoCuMnRuB nanobox decorated with a nanosheet array was synthesized for the first time by a "coordination-etch-reduction" method. The FeCoCuMnRuB nanobox has various structural characteristics to express the catalytic performance; meanwhile, it combines the high-entropy effect of multiple components with the electron trap effect induced by electron-deficient B, synergistically regulating its electronic structure. As a result, FeCoCuMnRuB nanobox exhibits enhanced OER activity with a low overpotential (η10 = 233 mV), high TOF value (0.0539 s-1), small Tafel slope (61 mV/dec), and a satisfactory stability for 200 h, outperforming the high-entropy alloy and low-entropy borides. This work develops a high entropy and electron-deficient B-driven strategy for motivating the catalytic performance of water oxidation, which broadens the structural diversity and category of high-entropy materials.

Protein-directed synthesis of fluorescent sulfur quantum dots for highly robust detection of pyrophosphate.

Inorganic pyrophosphate anions (PPi) play a key role in various biological processes and act as an essential indicator for physiological function evaluation and disease diagnosis. However, there is still a lack of available approaches for straightforward, robust, and convenient PPi detection. Herein, we design an on-off-on fluorescent switching nanoprobe employing Fe3+-mediated fluorescent sulfur quantum dots (SQDs) for highly robust detection of PPi. The bovine serum protein (BSA)-capped SQDs with fine water dispersibility and good optical stability are synthesized by an H2O2-assisted chemical etching reaction. Specifically, Fe3+ can strongly induce the aggregation of the SQDs into relatively larger sizes, resulting in aggregation-induced fluorescence quenching behavior. PPi can selectively bind with Fe3+ via emulative coordination and in preventing the aggregation of SQDs this is accompanied by recovery of fluorescence. The physicochemical properties of aggregated and disaggregated SQDs have been systematically investigated. Aggregation and disaggregation of the SQDs and the corresponding quenching and recovery of fluorescence occurs and guarantees the high-contrast sensing performance of the SQD system in complex and challenging aquatic environments. Our designed on-off-on nanoswitch holds great potential for the design of elemental quantum dot-based biosensors for the highly robust detection of analytes in the near future.

Negatively Charged Sulfur Quantum Dots for Treatment of Drug-Resistant Pathogenic Bacterial Infections.

Drug-resistant pathogenic bacteria as a worldwide health threat calls for valid antimicrobial agents and tactics in clinical practice. Positively charged materials usually achieve antibacteria through binding and disrupting bacterial membranes via electrostatic interaction, however, they also usually cause hemolysis and cytotoxicity. Herein, we engineered negatively charged sulfur quantum dots (SQDs) as an efficient broad-spectrum antibiotic to kill drug-resistant bacteria in vitro and in vivo. The SQDs can destroy the bacterial membrane system and affect their metabolism due to the intrinsic antibacterial activity of elemental sulfur and catalytic generation of reactive oxygen species, which exhibit effective therapeutic effect on subcutaneously implanted infection model induced by representative pathogenic Methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. Plus, the negatively charged surface makes the SQDs have excellent hemocompatibility and low toxicity, which all highlight the critical prospect of the SQDs as a potent biocompatible antibacterial agent in clinical infection therapy.

An Organic Hybrid Indium-Telluride Incorporating Binuclear Complexes [In2(ea)4]2+ with a Bridging Oxygen Donor.

The new organic hybrid indium-telluride [In2(ea)2Te2]n (1; Hea = ethanolamine) exhibits a new type of one-dimensional polymeric chain based on the linkages of dinuclear [In2(ea)4]2+ and [In2Te4]2- units, which offers the first example of an indium-telluride framework incorporating binuclear complexes [In2(ea)4]2+ with a bridging O donor. 1 shows a distinctive photocurrent response and photocatalytic properties under visible-light illumination.

Smartphone-based colorimetric assay of antioxidants in red wine using oxidase-mimic MnO2 nanosheets.

In this work, we report a fast and colorimetric method for the detection of antioxidants based on the oxidase-like activity of two-dimensional MnO2 nanosheets. Specifically, MnO2 nanosheets can transform the colourless substrate, 3,3',5,5'-tetramethylbenzidine (TMB), into a deep blue product (oxTMB) via catalytic oxidation, with a specific absorption peak arising at 652 nm. In the presence of antioxidants, both the dramatic colour fading and the decrease in absorbance at 652 nm are observed owing to the inhibition of catalytic oxidation of TMB, where MnO2 nanosheets can be transformed into Mn2+ with the aid of antioxidants. Based on the linear relationship between the absorbance at 652 nm and the concentration of the antioxidants, quantitative determination of antioxidants in the range of 0.1-12 µM has been achieved. Moreover, combined with smartphone-based technology, a portable colorimetric analytical platform for assay of antioxidants is further developed. This method shows advantages including easy operation, low cost, rapid detection and high sensitivity and has been successfully applied in the determination of total antioxidants in red wine.

Inserting Amide into NOTT-101 to Sharply Enhance Volumetric and Gravimetric Methane Storage Working Capacity.

Amide-functionalized NJU-Bai45 exhibits high volumetric and gravimetric CH4 working capacities of 190 cm3 cm-3 and 298 cm3 g-1 (from 5.8 to 65 bar), higher than that of the similar NJU-Bai43 (187 cm3 cm-3 and 292 cm3 g-1). This finding indicates that nitrogen-functionalized aromatic ring may not always play a positive role in amide-MOF for CH4 storage.

Accelerating the Peroxidase-Like Activity of Gold Nanoclusters at Neutral pH for Colorimetric Detection of Heparin and Heparinase Activity.

The peroxidase-like catalytic activity of gold nanoclusters (Au-NCs) is quite low around physiological pH, which greatly limits their biological applications. Herein, we found heparin can greatly accelerate the peroxidase-like activity of Au-NCs at neutral pH. The catalytic activity of Au-NCs toward the peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) oxidation by H2O2 was 25-fold increased in the presence of heparin at pH 7. The addition of heparin not only accelerated the initial catalytic rate of Au-NCs but also prevented the Au-NCs from catalyst deactivation. This allows the sensitive colorimetric detection of heparin at neutral pH. In the presence of heparinase, heparin was hydrolyzed into small fragments, weakening the enhancement effect of catalytic activity. On the basis of this phenomenon, the colorimetric determination of heparinase in the range from 0.1 to 3 µg·mL-1 was developed with a detection limit of 0.06 µg·mL-1. Finally, the detection of heparin and heparinase activity in diluted serum samples was also demonstrated.

Switchable fluorescence of MoS2 quantum dots: a multifunctional probe for sensing of chromium(VI), ascorbic acid, and alkaline phosphatase activity.

A simple strategy for modulating the fluorescence of MoS2 quantum dots (QDs) is described. The fluorescence of MoS2 QDs was firstly switched off by the addition of Cr(VI), and the quenched fluorescence was further switched on by introducing ascorbic acid (AA) into the mixture. The fluorescence quenching of MoS2 QDs by Cr(VI) was attributed to the fluorescence inner filter effect. After the addition of AA, Cr(VI) was reduced to Cr(III), and the fluorescence was restored. This finding has been applied for the fluorescent sensing of Cr(VI) in drinking water and AA in serum samples. In addition, the present method has been extended for turn-on sensing of an important biomarker alkaline phosphatase (ALP). There is a linear relationship between the fluorescence intensity and the concentrations of ALP in the range from 2.5 to 50 U/L, and the limit of detection is 0.34 U/L. The results showed MoS2 QDs hold great potential as a multifunctional fluorescent probe for the detection of metal ions, biological small molecules, and proteins. Graphical abstract The fluorescence of MoS2 QDs can be switched off by Cr(VI), and the quenched fluorescence can be further switched on by the addition of ascorbic acid or enzymatically generated ascorbic acid. This allows the selective detection of Cr(VI), ascorbic acid, and alkaline phosphatase based on the fluorescence of MoS2 QDs.

Water-soluble MoS2 quantum dots are a viable fluorescent probe for hypochlorite.

A method is described for the fluorometric determination of hypochlorite. It is making use of molybdenum disulfide quantum dots (MoS2 QDs) as a fluorescent probe. The QDs are prepared by hydrothermal reaction of sodium molybdate with glutathione. They possess diameters typically ranging from 1.4 to 3.8 nm, excellent stability in water, and blue photoluminescence (with excitation/emission peaks located at 315/412 nm and a quantum yield of 3.7%). The fluorescence of the QDs is statically quenched by hypochlorite, and the Stern-Volmer plot is linear. Hypochlorite can be detected in the 5-500 µM concentration range with a 0.5 µM detection limit. The method has been successfully applied to the determination of hypochlorite in spiked samples of tap water, lake water, and commercial disinfectants. Graphical abstract Schematic of a method for the fluorometric determination of hypochlorite using MoS2 quantum dots as a fluorescent probe. It has been applied to hypochlorite assay in spiked samples of tap water, lake water, and commercial disinfectants.

Operando chemistry of catalyst surfaces during catalysis.

Chemistry of a catalyst surface during catalysis is crucial for a fundamental understanding of mechanism of a catalytic reaction performed on the catalyst in the gas or liquid phase. Due to the pressure- or molecular density-dependent entropy contribution of gas or liquid phase of the reactants and the potential formation of a catalyst surface during catalysis different from that observed in an ex situ condition, the characterization of the surface of a catalyst under reaction conditions and during catalysis can be significant and even necessary for understanding the catalytic mechanism at a molecular level. Electron-based analytical techniques are challenging for studying catalyst nanoparticles in the gas or liquid phase although they are necessary techniques to employ. Instrumentation and further development of these electron-based techniques have now made in situ/operando studies of catalysts possible. New insights into the chemistry and structure of catalyst nanoparticles have been uncovered over the last decades. Herein, the origin of the differences between ex situ and in situ/operando studies of catalysts, and the technical challenges faced as well as the corresponding instrumentation and innovations utilized for characterizing catalysts under reaction conditions and during catalysis, are discussed. The restructuring of catalyst surfaces driven by the pressure of reactant(s) around a catalyst, restructuring in reactant(s) driven by reaction temperature and restructuring during catalysis are also reviewed herein. The remaining challenges and possible solutions are briefly discussed.

Role of anion polarizability in fluorescence sensitization of DNA-templated silver nanoclusters.

Fluorescent silver nanoclusters (Ag NCs) as novel fluorophores have received much attention because of their high brightness, good photostability and widely tunable emissions from the visible to the near-infrared range as a result of their size and existing environment. However, efforts are still needed to find the factors that tune the emission of Ag NCs. In this work, Ag NCs that were size-selectively grown on DNA were used to investigate the effect of the electronic properties of coordinating ligands. Halogen anions were used as the paradigm because of their periodicity in element properties. We found that addition of halogen anions did not alter the emission wavelength of Ag NCs, but the fluorescence intensity showed an initial increase at low concentrations of Cl(-), Br(-) and I(-) followed by a gradual decrease at high concentrations. No increase in fluorescence was observed for F(-) at either low or high concentration. Such specific halogen-anion sensitization of the fluorescence of Ag NCs suggests that the binding strength/manner and dipole polarizability of these anions synergistically tune the emission behavior of Ag NCs. Less fluorescence sensitization occurred for the anion having high enough polarizability to form a covalent bond with Ag NCs. The anion polarizability-sensitized fluorescence indicates the role of anion electronic properties in tuning the emission behavior of Ag NCs, which should be seriously considered in designing Ag NC-based sensors and devices.

Silencing RhoA inhibits migration and invasion through Wnt/ß-catenin pathway and growth through cell cycle regulation in human tongue cancer.

Ras homolog gene family member A (RhoA) has been identified as a critical regulator of tumor aggressive behavior. In this study, we assessed the role of RhoA in the mechanisms underlying growth, migration, and invasion of squamous cell carcinoma of tongue (TSCC). Stable RhoA knockdown of TSCC cell lines SCC-4 and CAL27 were achieved using Lentiviral transfection. The effects of RhoA depletion on cell migration, invasion, and cell proliferation were determined. The possible underlying mechanism of RhoA depletion on TSCC cell line was also evaluated by determining the expression of Galectin-3 (Gal-3), ß-catenin, and matrix metalloproteinase-9 (MMP-9) in vivo. Meanwhile, the underlying mechanism of TSCC growth was studied by analysis of cyclin D1/2, p21CIP1/WAF1, and p27Kip1 protein levels. Immunohistochemical assessments were performed to further prove the alteration of Gal-3 and ß-catenin expression. We found that, in mice injected with human TSCC cells in the tongue, RhoA levels were higher in primary tumors and metastasized lymph nodes compared with those in the normal tissues. Silencing of RhoA significantly reduced the tumor growth, decreased the levels of Gal-3, ß-catenin, MMP-9, and cyclin D1/2, and increased the levels of p21CIP1/WAF1 and p27Kip1. In vitro, RhoA knockdown also led to inhibition of cell migration, invasion, and proliferation. Our data suggest that RhoA plays a significant role in TSCC progression by regulating cell migration and invasion through Wnt/ß-catenin signaling pathway and cell proliferation through cell cycle regulation, respectively. RhoA might be a novel therapeutic target of TSCC.

Fabrication, Processing, Properties, and Applications of Closed-Cell Aluminum Foams: A Review.

Closed-cell aluminum foams have many excellent properties, such as low density, high specific strength, great energy absorption, good sound absorption, electromagnetic shielding, heat and flame insulation, etc. As a new kind of material, closed-cell aluminum foams have been used in lightweight structures, traffic collision protections, sound absorption walls, building decorations, and many other places. In this paper, the recent progress of closed-cell aluminum foams, on fabrication techniques, including the melt foaming method, gas injection foaming method, and powder metallurgy foaming method, and on processing techniques, including powder metallurgy foaming process, two-step foaming process, cast foaming process, gas injection foaming process, mold pressing process, and integral foaming process, are summarized. Properties and applications of closed-cell aluminum foams are discussed based on the mechanical properties and physical properties separately. Special focuses are made on the newly developed cast-forming process for complex 3D parts and the improvement of mechanical properties by the development of small pore size foam fabrication and modification of cell wall microstructures.

Dinuclear ytterbium(III) benzamidinate complexes with bridging S32-, Se22- and Te22- ligands: synthesis, structure and magnetic properties.

Treatment of Yb(II) complex [L2Yb(THF)2] (L = PhC(NSiMe3)2) with elemental sulfur, selenium or tellurium resulted in the isolation of a series of dinuclear Yb(III) complexes featuring side-on bound S32- (1), Se22- (2) or Te22- (3) moieties, respectively. Magnetic study on these complexes revealed that 3 is a rare lanthanide telluride single-molecule magnet (SMM).

Two-dimensional ß-MnOOH nanosheets with high oxidase-mimetic activity for smartphone-based colorimetric sensing.

Manganese (Mn) is a versatile transition element with diverse oxidation states and significant biological importance. Mn-based nanozymes have emerged as promising catalysts in various applications. However, the direct use of manganese oxides as oxidase mimics remains limited and requires further improvement. In this study, we focus on hydroxylated manganese (MnOOH), specifically the layered form ß-MnOOH which exhibits unique electronic and structural characteristics. The two-dimensional ß-MnOOH nanosheets were synthesized through a hydrothermal approach and showed remarkable oxidase-like activity. These nanosheets effectively converted the oxidase substrate, 3,3',5,5'-tetramethylbenzidine (TMB), into its oxidized form by initiating the conversion of dissolved oxygen into ·O2-, 1O2 and ·OH. However, in the presence of L-cysteine (L-Cys), the catalytic activity of ß-MnOOH was significantly inhibited, enabling highly sensitive detection of L-Cys. This sensing strategy was successfully applied for smartphone-based L-Cys assay, offering potential utility in the diagnosis of Cys-related diseases. The exploration of layered ß-MnOOH nanosheets as highly active oxidase mimics opens up new possibilities for catalytic and biomedical applications.

Preparation and Performance of Silicone Rubber Composites Modified by Polyurethane.

Silicone rubber composites with good comprehensive properties modified with polyurethane were obtained through mixing and vulcanizing methods. Firstly, the polyurethane prepolymer with double bonds was prepared by polytetrahydrofuran glycol (PTMG, Mn = 1000), isophorone diisocyanate (IPDI), and 2-hydroxyethyl methacrylate (HEMA). The prepolymer was then added to the silicone rubber compounds to prepare silicone rubber composites, combining the excellent properties of polyurethane with the silicone rubber materials. The effects of polyurethane content on the mechanical properties, insulation, hydrophobicity, thermal stability, and flame retardancy of composites were studied in detail. The results showed that the silicone rubber composites not only have good hydrophobicity, thermal stability and flame retardant properties, but the addition of polyurethane significantly improves the tensile strength at room and low temperatures and the volume resistivity of the materials. The tensile strength increased by 32.5%, and the volume resistivity nearly doubled. The excellent electrical insulation, high hydrophobicity and good mechanical properties make the silicone rubber composites appropriate for use in the field of polymeric house arresters.

The influence of different physical exercise amounts on learning burnout in adolescents: The mediating effect of self-efficacy.

Objective: To explore the effect of physical exercise on learning burnout in adolescents, and to reveal the mediating effect of self-efficacy between different physical exercise amounts and learning burnout. Methods: A total of 610 adolescents from 5 primary and middle schools in Chongqing, China were investigated with the Physical Exercise Rating Scale (PARS-3), the General Self-Efficacy Scale (GSES), and the Learning Burnout Scale (LBS). The SPSS21.0 and AMOS21.0 statistical software were used to process and analyze the data. Results: (1) The physical exercise amount in boys was significantly higher than that in girls, but there was no significant gender difference in self-efficacy and learning burnout. Meanwhile, the academic alienation and low sense of achievement of primary school students were significantly lower than that of junior high school students, and there was no significant difference in the physical exercise amount and self-efficacy. (2) The physical exercise amount in adolescents was positively correlated with self-efficacy (r = 0.41), negatively correlated with learning burnout (r = -0.46), and self-efficacy was negatively correlated with learning burnout (r = -0.45). (3) The physical exercise amount could directly and negatively predict the learning burnout of adolescents (ß = -0.40), and self-efficacy played a partial mediating effect between the amount of physical exercise and learning burnout (ES = -0.19). (4) Self-efficacy had no significant mediating effect between low exercise amount and learning burnout, but had a significant partial mediating effect between moderate (ES = -0.15) and high exercise amount (ES = -0.22) and learning burnout, and the partial mediating effect between high exercise amount and learning burnout was the highest. Conclusion: Physical exercise was an effective way to prevent or reduce learning burnout in adolescents. It can not only directly affect learning burnout, but also indirectly affect learning burnout through the mediating effect of self-efficacy. It should be pointed out that maintaining a sufficient amount of physical exercise is crucial to improving self-efficacy and reducing learning burnout.

Comparison and evaluation of different deep learning models of synthetic CT generation from CBCT for nasopharynx cancer adaptive proton therapy.

BACKGROUND: Cone-beam computed tomography (CBCT) scanning is used for patient setup in image-guided radiotherapy. However, its inaccurate CT numbers limit its applicability in dose calculation and treatment planning. PURPOSE: This study compares four deep learning methods for generating synthetic CT (sCT) to determine which method is more appropriate and offers potential for further clinical exploration in adaptive proton therapy for nasopharynx cancer. METHODS: CBCTs and deformed planning CT (dCT) from 75 patients (60/5/10 for training, validation and testing) were used to compare cycle-consistent Generative Adversarial Network (cycleGAN), Unet, Unet+cycleGAN and conditionalGenerative Adversarial Network (cGAN) for sCT generation. The sCT images generated by each method were evaluated against dCT images using mean absolute error (MAE), structural similarity (SSIM), peak signal-to-noise ratio (PSNR), spatial non-uniformity (SNU) and radial averaging in the frequency domain. In addition, dosimetric accuracy was assessed through gamma analysis, differences in water equivalent thickness (WET), and dose-volume histogram metrics. RESULTS: The cGAN model has demonstrated optimal performance in the four models across various indicators. In terms of image quality under global condition, the average MAE has been reduced to 16.39HU, SSIM has increased to 95.24%, and PSNR has increased to 28.98. Regarding dosimetric accuracy, the gamma passing rate (2%/2 mm) has reached 99.02%, and the WET difference is only 1.28 mm. The D95 value of CTVs coverage and Dmax value of spinal cord, brainstem show no significant differences between dCT and sCT generated by cGAN model. CONCLUSIONS: The cGAN model has been shown to be a more suitable approach for generating sCT using CBCT, considering its characteristics and concepts. The resulting sCT has the potential for application in adaptive proton therapy.

Colorimetric detection of total antioxidants in green tea with oxidase-mimetic CoOOH nanorings.

Green tea is a popular beverage and is widely consumed due to its taste and antioxidative polyphenols. Herein, a smartphone-based colorimetric reader using cobalt oxyhydroxide (CoOOH) nanorings has been successfully applied to detect antioxidants in green tea with high reliability and robustness. By exploiting the oxidase-mimicking activity, the as-synthesized CoOOH nanorings replaces natural enzymes to directly catalyze oxidate colorless 3,3 ´ ,5,5 ´ -tetramethylbenzidine (TMB), while antioxidants can disintegrate CoOOH, leading to an antioxidant concentration-dependent color change. Benefiting from the CoOOH nanorings-based colorimetric strategy, a smartphone-assistant nanosensor was devised for portable and visual detection of antioxidants in green tea. The proposed method can be extended to visual detection of a diverse range of diseases by responding to their specific antioxidant, and thus provide a pivotal disease toolbox that is compatible for development at the point-of-care.

Virtual reality combined with robot-assisted gait training to improve walking ability of children with cerebral palsy: A randomized controlled trial.

BACKGROUND: Children with cerebral palsy (CP) have disorders of posture and movement and which can limit physical activities such as walkingOBJECTIVE: This study aims to investigate the effectiveness of virtual reality (VR) combined with robot-assisted gait training (RAGT) on walking ability in children with CP and clarify the most effective degree of weight reduction. METHODS: Sixty CP children were recruited and randomly allocated into four different groups. The control group received conventional physical therapy (n= 15), and task groups performed VR combined with RAGT with 15% (Group A, n= 15) /30% (Group B, n= 15) /45% (Group C, n= 15) weight loss. All participants were given 50 min of therapy per session four times a week for 12 weeks and were assessed pre-and post-test with the surface electromyography (EMG), the Modified Ashworth Scale, the Gross Motor Function Measure (GMFM) dimension E and D, and Six-Minute Walking Test (6-MWT). RESULTS: All indicators had improved significantly in each group after the intervention (P< 0.05). The result of our study demonstrated that the more effective impacts of VR combined with RAGT on walking ability compared to the control group (P< 0.05), and 30% of weight loss had the best improvement in CP children (P< 0.01). CONCLUSIONS: VR combined RAGT can effectively improve walking ability in children with CP, especially when the weight loss is 30%.